Heat oven to 220C/fan 200C/gas 7.
Lay the fillets, skin-side down, brush them
with mustard and lay a slice of pancetta on
each. Starting from the tail end, roll the fillet
up with the pancetta into a spiral, then secure
with a toothpick, a bay leaf and a lemon slice.
Sit the fillets in a baking tray or ceramic dish.
Drizzle the fillets with olive oil, then roast
for 15-20 mins until cooked through and
starting to brown at the edges. Serve 2 fillets
per person with new potatoes or a crunchy
apple and onion salad.